Nantucket BESS

Project Reference: National Grid BESS - NWA

Nantucket Island Battery Energy Storage System Integration & Testing

Quanta Technology was engaged to prepare test plans for commissioning, site acceptance testing and performance evaluation of the National Grid owned battery energy storage system (BESS) on Nantucket Island. A combination of new Combustion Turbine and BESS as an non-wires alternative (NWA) approach was designed and installed to meet the need of an N-1 condition in the management of overloads on two undersea cables that connect the island to the mainland, and to support islanding of the system under loss of both cables. Secondary use cases foresee participation to the broader power system market, when the BESS is not needed for these primary use cases.

During initial project discussion involving the review of the vendor test procedures and site design documents, it was noted that several additional test categories would need to be considered to ensure the system would perform satisfactorily under all intended condition. Quanta Technology lead the development of the overall test plan and ultimately a total of 6 categories of tests beyond those submitted by vendor were developed and tested as part of the final project scope.

Fig. Location of Nantucket island and Undersea Cables Serving the Island
Fig. Layout of Bunkers Road Generation Plant and Photo of Battery Energy Storage Installation

Test Plan Development and Support

Quanta Technology developed the overall test plan through discussions with National Grid and by including the Combustion Turbine Generator and BESS vendors, and consultation of industry standards and best practices. The final test plan intended to ensure the total set of functionality could be tested under all anticipated operating conditions. The document outlines tests for the following six test categories :

  • BESS Preparation Tests
  • BESS Category A Tests – Basic Functionality
  • BESS Category B Tests – Charge and Discharge Characterization
  • BESS Category C Tests – Supplementary Tests for characterization and Volt-Var tests
  • BESS Category D Tests – Application Testing
  • BESS Category E Tests – Advanced Applications

Quanta Technology also helped prepare a test setup for Islanding and Black Start test, by using load banks to separate the BESS and the other rotating generator from the distribution system for those specific tests that required change of frequency and voltage. Quanta Technology also assisted National Grid to perform several studies to determine proper settings for the BESS inverter parameters (ride through protection, and Volt-Var curves) to coordinate the BESS protection with the feeder and substation protection

BESS Services

  • Owner’s Engineer – Review of Design and Engineering: Subject Matter Expert review of design drawings, engineering studies, specifications, test plans and witnessing of acceptance testing and commissioning.
  • BESS Test Plan Development: Development of FAT, SAT, and commissioning with goal of BESSs application.
  • BESS Integration and Performance Assessment: Support integration and commissioning of the system
  • Training: Prepare and deliver on-site training on all aspects of design, test plans, system commissioning and on-going operation and maintenance.

Application Testing Summary

During site acceptance tests, Quanta Technology worked with BESS vendor to verify the communications and remote controls, as well as troubleshooting of several autonomous controls (e.g. Volt-VAR) and applications (peak shaving). The key issues were the differences in the way vendor implemented certain controls, versus how it should be done from the utility and grid supporting perspective.

Several shortcomings were identified in the vendor control which led to development of an owner site controller and island forecasting system to provide additional BESS functionalities and an interface for future advanced controls based on load and generation forecast, and scheduling.

Quanta Technology also utilized the knowledge gained during the tests and feedback from discussions with stakeholders to prepare a set of design guidelines and operational manual for the BESS site.


The test plan developed and implemented by Quanta Technology delivered a thorough understanding of the vendor controls and limitations to deliver the intended applications. Overall the project benefitted from detailed performance analysis and several limitations were circumvented through close collaboration between all stakeholders. The project added unique valuable experience to Quanta Technology’s extensive portfolio of BESS testing and commissioning projects.

Fig. Interconnection Diagram of BESS and interfacing of BESSTI

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